US20020180371A1 - Display device and method of manufacturing the same - Google Patents

Abstract

The object of the present invention is to propose a structure of a display device in which water is prevented from passing through the side faces of a display device using an organic light-emitting element and a gap between substrates is made uniform. On the first substrate having the light-emitting element provided thereon, the thicknesses of the layers deposited in the peripheral area, the pixel portion and the driving circuit portion are equalized with each other. Furthermore, an adhesive is provided as thin as possible in the peripheral area of the first substrate so as to bond a second substrate to the first substrate. As a result, the distance between the first substrate and the second substrate can be made uniform throughout the peripheral area of the first substrate, the pixel portion and the driving circuit. Moreover, since a protective film overlying the organic light-emitting element is also provided on the side faces of the second insulating film, water is prevented from entering the display device through its side faces.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0001]
• The present invention relates to a display device using an organic light-emitting element and a manufacturing method thereof. More specifically, the present invention relates to a sealing structure for protecting an organic light emitting element deposited onto a substrate, and to a display device, in which an element substrate (a substrate having at least an element such as a TFT) and a sealing substrate are provided in the proximity, and a manufacturing method thereof.[0002]
• Throughout the specification, the term “organic light-emitting element” indicates an element including an organic compound film sandwiched between two electrodes to achieve light emission. One of the representative organic light-emitting elements is a light-emitting element using an organic light-emitting diode (OLED). The OLED includes an organic compound film sandwiched between two electrodes. Holes are injected to one of the electrodes while electrons are injected to the other electrode. The holes and the electrons are therefore coupled with each other to cause light emission.[0003]
• 2. Description of the Related Art[0004]
• In recent years, display devices using the organic light-emitting element are actively studied. The display devices using the organic light-emitting element can be reduced in weight as well as in thickness as compared with a conventional CRT, and thus their application to various uses is attempted. Portable telephones and personal digital assistants (PDAs) can be now connected to the Internet, resulting in a remarkable increase in the amount of information to be displayed as images. Accordingly, there arises an increasing demand for display devices to perform color display and to enhance their definition.[0005]
• On the other hand, light weight is an important factor for the display device included in such a portable digital assistant. For example, a portable phone having less than 70 g in weight is now on the market. In order to reduce the weight of the portable digital assistant itself, a throughout review as to the weight of almost all the used components such as individual electric components, a body and a battery is performed. In order to realize a further reduction in weight, however, it is necessary to lighten the display device itself.[0006]
• Since a display device including a pixel portion formed with an organic light-emitting element is a self-light emitting type display device, a light source such as a backlight is not required as is needed in liquid crystal display devices. Therefore, such a display device using the organic light-emitting element is promising means of realizing light weight and a thin body.[0007]
• The organic light-emitting element is capable of emitting blue light and thus allows the realization of a full-color display self-light emitting type display device. However, various deterioration phenomena are observed in the organic light-emitting element. It is urgently required to eliminate such phenomena as obstacles to the practical use of the organic light-emitting element.[0008]
• For example, the dark spot, which is a non-light emitting point defect appearing in a pixel portion, is regarded as a problem that remarkably reduces the display quality. It is said that the dark spot is a progressive defect and the mere presence of water increases the number of dark spots even if the organic light-emitting element is not operated. It is believed that the cause of the dark spot is a high reactivity of a cathode containing an alkali metal or an alkali earth metal with water or oxygen.[0009]
• Therefore, in the display device using the organic light-emitting element, a desiccant is placed in a sealed region surrounded by an element substrate, a sealing substrate and a sealing agent so that water and oxygen do not enter the organic light-emitting element. FIG. 15 is a cross-sectional view showing a display device using a conventional organic light-emitting element. An[0010]element substrate301 made of glass, on which an organic light-emittingelement307 is provided, and asealing substrate303 provided so as to be opposed to theelement substrate301, are bonded to each other through asealing agent302 so that the organic light-emitting element is prevented from being exposed to the outside air. A fineprotective film308 having a thickness of 100 nm to 500 nm may be further provided on the organic light-emittingelement307 so as to prevent water from entering the organic light-emitting element307. A sealed region is filled with dry air. A distance between theelement substrate301 and thesealing substrate303 is adjusted by mixing a filler, a spacer or the like into thesealing agent302.
• The sealing[0011]substrate303 has a hollow region made of a metal such as stainless steel or aluminum, which is processed into a dish-like shape. A desiccant304 and afilm sheet305 are provided in the hollow region. Thedesiccant304 has moisture-absorption characteristics so as to absorb water penetrating into the sealed region to prevent the degradation of the organic light-emitting element. If thedesiccant304 gets into the display area where the organic light-emitting element307 is provided, display performance of the device is deteriorated. Thus, thefilm sheet305 having a permeability to gas and vapor is bonded to the sealingsubstrate303, thereby confining thedesiccant304 within a concave portion of thesealing substrate303. Thefilm sheet305 has a thickness of 100 to 300 μm. In consideration of flexion of thefilm sheet305 generated by the weight of thedesiccant304, a gap between thefilm sheet305 and the organic light-emittingelement307 where they are bonded to each other so as not to be in contact is required to be 50 to 200 μm. Accordingly, with thefilm sheet305 provided in the hollow region of thesealing substrate303, the hollow region is required to have a depth of at least 150 to 500 μm. The placement of thefilm sheet305 or the like increases the distance between the element substrate and the sealing substrate, making it difficult to reduce the thickness of the display device. In view of this problem, the present invention has been made and a first object of the present invention is to provide a display device, in which theelement substrate301 and thesealing substrate303 can be provided in close proximity to each other so as to enable the reduction in thickness of the device, and a manufacturing method thereof.
• Conventionally, in order to provide the hollow region in the sealing substrate where the desiccant is placed, it is required to use a sealing substrate made of a metal material that is easy to process. In the display device including the sealing substrate made of metal, however, the[0012]element substrate301 made of glass can be uniquely used as a substrate through which light emitted from the organic light-emitting element is output. Thus, if thin film transistor (TFT) elements are provided on the element substrate, light emitted from the organic light-emitting element is obtained from the side of the element substrate through the TFT elements, resulting in lowered brightness of the emitted light. Moreover, the thinner the element substrate becomes, the lower the shock resistance becomes. As a result, the element substrate is likely to be fragile. In particular, when the sealing substrate made of metal and the element substrate made of glass are bonded to each other, the distortion is generated by a sudden change in temperature due to the difference in thermal expansion coefficient, causing the cracking in the element substrate.
• Accordingly, a second object of the present invention is to provide a display device achieving a bright display with good visibility by increasing the brightness of light emitted from the organic light-emitting element and a manufacturing method thereof. In addition, a third object of the present invention is to provide a display device, in which breakage due to a sudden change in temperature is restrained and a manufacturing method thereof.[0013]
• Furthermore, the sealing agent placed on the side faces of the display device is made of an organic resin material, which has a high moisture permeability as compared with inorganic type glass materials and metal materials. For example, the organic resin material has a permeability of 15 g/m[0014]²for 24 hr. to 30 g/m²for 24 hr. at 60° C. and a humidity of 90%. Although the amount of water penetrating into the sealed region through the element substrate made of glass from the front side of the display device and the amount of water penetrating into the sealed region through the sealing substrate made of a metal material from the rear side of the display device are negligibly small, water which enters the sealed region through the sealing agent having a high moisture permeability from the side faces of the display device causes the deterioration of the organic light-emitting element. Thus, it is necessary to take measures to cope with this problem.
• Since the amount of water passing through the sealing agent is determined by the product of the area of the sealing agent exposed to the outside air multiplied by the moisture permeability of the sealing agent, it is preferred that the area of the sealing agent exposed to the outside air is as small as possible, that is, the sealing agent is as thin as possible. However, the sealing agent serves not only to bond the sealing substrate and the element substrate to each other, but also to control the distance between the sealing substrate and the element substrate. Thus, it is necessary to determine the thickness of the sealing agent in consideration of the distance between the element substrate and the sealing substrate so that the element substrate and the sealing substrate do not come in contact with each other to break the organic light-emitting element provided on the element substrate and the transistors that make a current flow through the organic light-emitting element.[0015]
• In view of the above problem, a fourth object of the present invention is to provide a display device with enhanced reliability, in which the element substrate and the sealing substrate can be provided close to each other and the amount of water vapor passing from the side faces of the element device through an organic resin material such as a sealing agent to enter the sealed region is reduced so as to prolong the lifetime of the organic light-emitting element; and a manufacturing method thereof.[0016]
• Alternatively, in order to reduce the amount of water entering from the side faces of the display device, a protective film having a low permeability to a fine gas and water vapor may be considered to be provided between the sealing agent and the outside air so as to contact the sealing agent. However, the formation of the protective film on the side faces of the sealing agent by using a vacuum apparatus after bonding the element substrate and the sealing substrate to each other through the sealing agent leads to an increase in manufacturing cost, thereby decreasing the advantages of the organic light-emitting element which is easily manufactured at a low cost. In addition, since a stress is applied onto a material that is applied onto the substrate by a dispenser system so as to cure the sealing agent, the sealing agent after curing has a gently undulating shape in the thickness direction between the substrates on the side faces of the sealing agent as well as in the width direction perpendicular to the thickness direction of the side faces of the sealing agent. It is difficult to form the protective film on such side faces of the sealing agent, whereby providing a part where the protective film is not formed.[0017]
• As described above, it is difficult to reduce the amount of water passing through the sealing agent provided on the side faces of the display device. Accordingly, in the display device using the organic light-emitting element, there is a great need to reduce water passing through the side faces of the display device. Consequently, the fourth object of the present invention is important.[0018]
• In addition to the appropriate realization of the first to fourth objects, the present invention enables the reduction in the number of paths through which water passes from the outside air and the control for making the distance between the element substrate (first substrate) and the sealing substrate (second substrate) uniform.[0019]
SUMMARY OF THE INVENTION
• As one example of a structure of the present invention, when a bank is to be formed on the element substrate, an insulating film is formed in a closed curve form in the periphery of the element substrate in the same step of forming the bank. Then, an adhesive is formed on the insulating layer, which serves to bond the element substrate and the sealing substrate to each other. The adhesive is formed to have a small thickness, i.e., 0.05 to 0.5, μm. With the structure of the present invention, it is possible to provide the element substrate and the sealing substrate in the proximity, thereby achieving the first object of the present invention, that is, the reduction in thickness of the display device.[0020]
• Furthermore, if substrates made of glass having light transmittance are used as the element substrate and the sealing substrate, light emitted from the organic light-emitting element can be obtained from the side of the sealing substrate. In this case, an aperture ratio of each pixel is determined, independently of the ratio of the number of TFT elements to a pixel. As a result, display with high brightness can be realized, thereby achieving the second object of the present invention. In addition, the breakage due to a sudden change in temperature is restrained, because the element substrate and the sealing substrate have the same thermal expansion coefficient. Consequently, the third object of the present invention is achieved.[0021]
• Furthermore, if the element substrate and the sealing substrate are provided in the proximity, the amount of water passing through the organic resin material (adhesive), which serves to bond the element substrate and the sealing substrate to each other, is reduced. As a result, the lifetime of the organic light-emitting element is expected to be prolonged, thereby achieving the fourth object of the present invention.[0022]
• In the case where the element substrate and the sealing substrate are provided in the proximity, protections of the organic light-emitting element provided on the element substrate and of the transistors become important. Moreover, how and where to provide the desiccant becomes also an important factor, depending on the desired lifetime. This point will be appropriately described.[0023]
• A method of enhancing the uniformity between the element substrate and the sealing substrate will be also appropriately described.[0024]
BRIEF DESCRIPTION OF THE DRAWINGS
• In the accompanying drawings:[0025]
• FIG. 1 is a cross-sectional view showing a display device using an organic light-emitting element according to Embodiment Mode 1;[0026]
• FIG. 2 is a cross-sectional view showing a display device using an organic light-emitting element according to Embodiment Mode 2;[0027]
• FIG. 3 is a cross-sectional view showing a display device using an organic light-emitting element according to Embodiment Mode 3;[0028]
• FIG. 4 is a cross-sectional view showing a display device using an organic light-emitting element according to Embodiment Mode 4;[0029]
• FIG. 5 is a cross-sectional view showing a display device using an organic light-emitting element according to Embodiment Mode 5;[0030]
• FIG. 6 is a top plan view showing the appearance of a display device using the organic light-emitting element according to Embodiment Mode 1;[0031]
• FIG. 7 is a top plan view showing the appearance of a display device using the organic light-emitting element according to Embodiment Mode 4;[0032]
• FIG. 8 is a top plan view showing the appearance of a display device using the organic light-emitting element according to Embodiment Mode 5;[0033]
• FIG. 9 is a top plan view showing a pixel portion in Embodiment 1;[0034]
• FIG. 10 is a cross-sectional view of an active matrix substrate of Embodiment 1;[0035]
• FIG. 11 is an equalizing circuit in the pixel portion of Embodiment 1;[0036]
• FIGS. 12A to[0037]12D are perspective views illustrating examples of electronic devices of Embodiment 3;
• FIGS. 13A to[0038]13C are perspective views illustrating examples of electronic devices of Embodiment 3;
• FIG. 14 is a perspective view illustrating a method of cutting a glass substrate by the use of a CO[0039]₂laser in Embodiment 2; and
• FIG. 15 is a cross-sectional view showing a display device using a conventional organic light-emitting element.[0040]
DESCRIPTION OF THE PREFERRED EMBODIMENT MODES
• Hereinafter, the preferred embodiment modes of the present invention will be described with reference to the accompanying drawings.[0041]
• One example of the present invention is now described with reference to a cross-sectional view shown in FIG. 1. FIG. 1 shows a display device using an organic light-emitting element according to the present invention. A[0042]first substrate100 is a light transmitting substrate made of glass. A TFT in apixel portion121 and a TFT in adriving circuit portion120 provided in the periphery of thepixel portion121 are formed on thefirst substrate100.Base films118 and119 made of an inorganic material are provided on thefirst substrate100. Each of the TFTs in the pixel portion and the driving circuit portion on the first substrate, includes: asemiconductor film110; agate insulating film111 covering thesemiconductor film110;gate electrodes112 and113 provided above a channel region of thesemiconductor film110 through thegate insulating film111; a firstinterlayer insulating film114 made of an inorganic material, covering thegate electrodes112 and113 and thegate insulating film111; a secondinterlayer insulating film115 made of an organic material, provided on the firstinterlayer insulating film114; and adrain electrode116, asource electrode117 and awiring122, formed by patterning the same conductor layer. One end of thewiring122 is connected to thesemiconductor film110 in the driving circuit portion, and the other end serves as an external input terminal provided outside a sealed region. An FPC (flexible print circuit) is connected to the external input terminal through afirst electrode103 made of an ITO film.
• An organic light-emitting[0043]element106 consisting of a laminate of thefirst electrode103, anorganic compound film104 and asecond electrode105 is provided on thesecond interlayer film115. Thefirst electrode103 is an anode, for which a transparent conductive film having light transmittance, for example, an ITO (Indium Tin Oxide) film can be used. Thesecond electrode105 is a cathode, for which a thin metal film containing an alkali metal or an alkali earth metal such as MgAg or AlLi can be used. In order to prevent the breaking of theorganic compound film104 at the end of thefirst electrode103 due to the weight of thefirst electrode103 to cause the short-circuit between thefirst electrode103 and thesecond electrode105 at the broken point, a bank is provided so as to cover the end of thefirst electrode103. Theorganic compound film104 is provided along the gentle slope of the bank, and then thesecond electrode105 is provided thereon, so that the short-circuit between thefirst electrode103 and thesecond electrode105 can be prevented. In the present invention, an insulating film having a thickness of 1 to 10 μm is patterned to form a firstinsulating film107 serving as the bank and a secondinsulating film108 provided in the periphery of thefirst substrate100.
• For the propose of restraining water from entering the display device through its side faces and the reaction between the organic light-emitting element and water, a[0044]protective film109 is formed as an uppermost layer on thefirst substrate100 so as to cover thesecond electrode105, the first and second insulatingfilms107 and108 and the secondinterlayer insulating film115. At the same time, theprotective film109 is also formed on the organic light-emittingelement106, the side faces of the secondinterlayer insulating film115, and the side faces of the secondinsulating film108. Since the side faces of the secondinterlayer insulating film115 and the secondinsulating film108 are insulated from the outside air by the fine and hardprotective film109, water is prevented from passing through the side faces of the display device to enter the sealed region. As theprotective film109, a silicon nitride film or a DLC (Diamond like Carbon) film may be used. The DLC film is optimal as theprotective film109 because the DLC film is very hard and has excellent insulation properties, and thus can have a low gas permeability to vapor, oxygen or the like. In this manner, theelement substrate100, on which the organic light-emittingelement106 is formed, is completed.
• An adhesive[0045]102 is provided above the secondinsulating film108 which is provided in the periphery of theelement substrate100 so as to bond theelement substrate100 and a sealingsubstrate101 to each other. The sealingsubstrate101 is a second substrate having light transmittance. The adhesive102 has a small thickness, i.e., a thickness of 0.05 to 0.5 μm, preferably, 0.05 to 0.2 μm. If the total thickness of the layers deposited under the adhesive102 and the total thickness of the layers deposited in the pixel portion where the first insulatingfilm107 is provided, are adjusted to be equal to each other, the distance between thefirst substrate100 and thesecond substrate101 can be made uniform throughout the pixel portion and the peripheral area of thefirst substrate100. More desirably, in further consideration of the thickness of the adhesive102, when the sum of the thickness of the adhesive102 and the total thickness of the underlying layers in the peripheral area of thefirst substrate100 is designed to be equal to the total thickness of the deposited layers in the pixel portion where the first insulating film is provided or to the total thickness of the deposited layers in the driving circuit portion, the distance between thefirst substrate100 and thesecond substrate101 can be more certainly uniform throughout the pixel portion and the peripheral area of thefirst substrate100. To achieve such uniformity, a film having a dominant thickness in the laminate, for example, a second interlayer insulating film, a bank and an insulating film formed in the same manufacturing step as the bank, is required to be provided in the pixel portion, the driving circuit portion and the peripheral area of thefirst substrate100.
• The reduction in thickness of the adhesive[0046]102 allows the reduction in the amount of water passing from the outside air through the side faces of the adhesive102 to enter the sealed region. Since an adhesive having adhesion and such characteristics that provide a thickness of 0.05 to 0.5 μm, preferably, 0.05 to 0.2 μm can be used in the present invention, even a conventional sealing agent may be used as an adhesive of the present invention as long as it has a thickness of 0.05 to 0.5 μm, preferably, 0.05 to 0.2 μm.
• The sealed region surrounded by the[0047]element substrate100, the sealingsubstrate101 and the adhesive102 is filled with a dry gas. An inert gas such as nitrogen, argon, or helium is used as the dry gas. The dry gas contains a very small amount of the remaining water. However, since the adhesive102 has a small thickness, i.e., a thickness of 0.05 to 0.5 μm, preferably, 0.05 to 0.2 μm, the volume of the sealed region, that is, the volume of the dry gas filling the sealed region is also small. Thus, the amount of water remaining in the dry gas within the sealed region is correspondingly small.
• Moreover, since the moisture permeability of the organic resin film tends to be lowered if its width is large, it is preferred that the width of the organic resin film is increased by providing the second insulating film made of the organic resin film, which is formed in contact with the protective films on the side faces of the display device, so as to cover not only the underlying portion of the adhesive[0048]102 but also the drivingcircuit portion120. However, if the area of a frame region is increased with the increase in the width of the second insulating film, the display performance is degraded. Thus, the width of the second insulating film is preferably 100 to 5000 μm. The designer can appropriately design the width of the second insulating film because it is determined by a photomask.
• According to the present invention, since the protective film can be provided without unevenness on the side faces of the display device in simple manufacturing steps, the amount of water passing through the side faces of the display device to enter inside can be reduced. The organic resin material, which is exposed to the outside air on the side faces of the display device, serves as an adhesive. Since the adhesive can be made thinner as far as the material permits, the area of the adhesive exposed to the outside air can be reduced to be as small as possible.[0049]
• In addition, the use of the second substrate made of glass as the sealing substrate allows the thermal expansion coefficients of the element substrate and the sealing substrate to be equal to each other. As a result, since the element substrate and the sealing substrate have the same thermal expansion coefficient, the cracking in the substrates in accordance with a change in temperature can be prevented from occurring even if the temperature of the environment where the device is used is suddenly changed. The present invention is particularly effective when the strength of the substrates is lowered with the reduction of their thickness. Certainly, since the element substrate and the sealing substrate are both made of glass having light transmittance, light emitted from the organic light-emitting element can be obtained from the side of the element substrate, with a first electrode of the organic light-emitting element being light transmissive and a second electrode being light reflective. On the contrary, light emitted from the organic light-emitting element can be obtained from the side of the sealing substrate, with the first electrode being light reflective and the second electrode being light transmissive. The designer may appropriately determine from which substrate, i.e., the element substrate or the sealing substrate, light emitted from the organic light-emitting element is to be obtained.[0050]
• The structure shown in FIG. 1 is intended to prolong the lifetime of the light-emitting element by providing the fine protective film on the side faces of the display device and the organic light-emitting element. The long-term reliability of the organic light-emitting element can be ensured by various methods in the embodiment modes described below. Furthermore, a method of providing a desiccant in the above structure will be also described. With the following embodiment modes, the uniformity of the distance between the first substrate and the second substrate of the organic light-emitting element can be improved by various methods. The following embodiment modes may be combined. Hereinafter, the present invention will be described in detail by way of example.[0051]
• Embodiment Modes[0052]
• (Embodiment Mode 1)[0053]
• A first embodiment mode of the present invention will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view showing an active-matrix display device using an organic light-emitting element. The components constituting the display device shown in FIG. will be described in the order of formation.[0054]
• A[0055]driving circuit portion120 and apixel portion121 are formed by using TFTs on afirst substrate100. As thefirst substrate100, a substrate made of glass such as barium borosilicate glass, alumino borosilicate glass, or quartz glass is used.
• The TFT in the[0056]driving circuit portion120 and the TFT in thepixel portion121 are provided onbase films118 and119 having insulation properties. A silicon nitride oxide film having a thickness of 10 to 100 μnm is formed as thebase film118, whereas a silicon nitride oxide film having a thickness of 20 to 200 nm is formed as thebase film119. In this embodiment mode, silicon nitride oxide films having different film qualities are deposited to form thebase films118 and119.
• The TFT is constituted by a[0057]semiconductor film110, agate insulating film111,gate electrodes112 and113, a firstinterlayer insulating film114, a secondinterlayer insulating film115, adrain electrode116 and asource electrode117. A silicon film having a thickness of 10 to 150 nm is formed as thesemiconductor film110, and a nitride film having a thickness of 20 to 300 nm is formed as thegate insulating film111. A laminate film including a tantalum nitride film having a thickness of 30 to 60 nm and a tungsten film having a thickness of 370 to 400 nm is formed as each of thegate electrodes112 and113. A silicon oxide film having a thickness of 50 to 150 nm is formed as the firstinterlayer insulating film114, whereas an acrylic resin film having a thickness of 1 to 3 μm is formed as the secondinterlayer insulating film115. As each of thedrain electrode116 and thesource electrode117, a laminate including a titanium film having a thickness of 50 to 800 nm, an aluminum alloy film containing aluminum as a main constituent, to which silicon is added as an impurity element, having a thickness of 350 to 400 nm, and a titanium film having a thickness of 100 to 1600 nm, is formed. Aconductor film123, awiring122 and awiring124 are formed of the same layer as thedrain electrode116 and thesource electrode117.
• As an anode, the[0058]first electrode103 made of an ITO (Indium Tin Oxide) film, which is a conductive film having light transmittance, is formed. Thefirst electrode103 may be formed to have a thickness of 100 to 200 nm.
• A bank made of a photosensitive organic resin film such as acrylic or polyimide is formed so as to partially overlap the end of the[0059]first electrode103. A thickness of the bank is set to 1 to 10 μm. A photosensitive acrylic resin film is patterned to form a firstinsulating film107 in a striped manner along a source wiring as the bank. A secondinsulating film108 is formed so as to cover the peripheral area of thefirst substrate100 and the drivingcircuit portion120.
• The formation of an[0060]organic compound film104 in a striped manner along a gentle slope of the bank prevents the breaking of theorganic compound film104 at the end of thefirst electrode103, which in turn prevents the short-circuit between thefirst electrode103 and thesecond electrode105 due to the broken point of theorganic compound film104. Theorganic compound film104 is deposited in the order of: electron transport layer/light emitting layer/hole transport layer/hole injection layer. However, theorganic compound film104 may alternatively have a structure of: electron transport layer/light emitting layer/hole transport layer; or electron injection layer/electron transport layer/light emitting layer/hole transport layer/hole injection layer. In the present invention, any conventional structures may be used.
• As specific examples of the light emitting layers, the following layers may be used: as a layer emitting red light, cyanopolyphenylene; as a layer emitting green light, polyphenylene vinylene; and as a layer emitting blue light, polyphenylene vinylene or polyalkylphenylene. A thickness of the light emitting layer may be set to 30 to 150 nm.[0061]
• Since the above-mentioned materials are merely examples of the materials that can be used for the light emitting layers, the materials are not limited thereto. Materials for forming the light emitting layer, the hole transport layer, the hole injection layer, the electron transport layer and the electron injection layer may be freely selected in the possible combinations thereof.[0062]
• As the[0063]second electrode105, a cathode is made of a material containing magnesium (Mg), lithium, (Li) or calcium (Ca) having a small work function. Preferably, an electrode made of MgAg (a material obtained by mixing Mg and Ag at the ratio of Mg:Ag=10:1) may be used. Besides, an MgAgAl electrode, an LiAl electrode, and an LiFAl electrode can be cited as examples of thesecond electrode105. Thesecond electrode105 is formed by using a material such as MgAg or LiF. A thickness of thesecond electrode105 may be set to 100 to 200 nm. Thesecond electrode105 is formed in a striped manner between the banks, serving as a common electrode which is short-circuited outside the display area.
• The organic light-emitting[0064]element106 is formed by depositing thefirst electrode103, theorganic compound film104, and thesecond electrode105 in this order. Thefirst electrode103 serves as a cathode having light reflectance, whereas thesecond electrode105 serves as an anode having light transmittance, thereby allowing light emitted from the organic light-emittingelement106 to be output toward the side of thefirst substrate100.
• As a[0065]protective film109, a DLC film having a thickness of 100 to 500 nm is used. The DLC film can be formed by a plasma CVD method, a microwave CVD method, an electron cyclotron resonance (ECR) CVD method, a sputtering method or the like. With any film formation method, the DLC film having good adhesion can be formed without heating the organic compound film. The DLC film is formed with the substrate being placed on the cathode. Alternatively, a negative bias is applied onto the substrate to form a fine and hard DLC film by utilizing the ion impact to some extent. As a reaction gas used for film growth, a hydrocarbon type gas, for example, CH₄, C₂H₂, C₆H₆or the like is used. The reaction gas is ionized by glow discharge. The resulting ions are accelerated to collide against the cathode, across which a negative self-bias is applied, thereby forming the DLC film. In this method, a fine and smooth DLC film can be obtained. Since the substrate is scarcely heated to form the DLC film, the DLC film can be formed in the last manufacturing step of thefirst substrate100. The DLC film is provided so as to cover thesecond electrode105, the first insulatingfilm107 and the secondinsulating film108.
• As the adhesive[0066]102, an epoxy type adhesive is used. Either an ultraviolet-curable resin or a heat-curable resin can be used as the adhesive102. It is preferred to select a material for the adhesive102 in consideration of a heat resistance temperature of the organic light-emittingelement106. It is desired that the adhesive102 is formed as thin as possible. As the adhesive102, LIXON BOND, LX-0001 distributed by Tisso Co. Ltd. may be used. The lixon bond, LX-0001, is a two-part epoxy resin. After the application of LX-0001 on thefirst substrate100, LX-0001 is cured at 100° C. for two hours, applying the stress on the periphery of thefirst substrate100 and thesecond substrate101. After the curing, the adhesive102 can be formed to have a thickness of 0.2 to 0.5 μm by adjusting the stress and the amount of application. In Embodiment Mode 1, the distance between thefirst substrate100 and thesecond substrate101 is controlled by the total thickness of thebase films118 and119, thegate insulating film111, the firstinterlayer insulating film114, the secondinterlayer insulating film115, thewiring122 or theconductor film123, the secondinsulating film108 and the adhesive102. In this laminate structure, the adhesive102 is not required to have a function of controlling the gap. Since it is sufficient for the adhesive102 to have an adhesion function for bonding the substrates to each other, it is preferred that the adhesive102 is formed as thin as possible so as to reduce the area of the adhesive102 made of an organic resin material, which is exposed to the outside air on the side faces of the display device.
• As the sealing[0067]substrate101, a second substrate made of glass such as barium borosilicate glass, alumino-borosilicate glass, or quartz glass is used.
• Although not shown, the stripe-shaped[0068]second electrode105 is short-circuited outside the display area to serve as a common electrode. In the region designated by a chain line B-B′, one end of thewiring124 is in contact with thesecond electrode105. The other end of thewiring124 serves as an external input terminal.
• The[0069]conductor film123 below the adhesive102 is provided to equalize the total thickness of the laminate film below the adhesive102 so that the distance between thefirst substrate100 and thesecond substrate101 is uniformed in the region surrounded by the adhesive102. Theconductor film123 is provided so as to cover the upper face and the side faces of the secondinterlayer insulating film115 made of an organic resin film except the region where the external input terminal is provided, thereby preventing water from passing through the side faces of the secondinterlayer insulating film115 to enter the inside of the display device.
• Although not shown, the surface of the sealing[0070]substrate101 may be scraped off by a sandblast method so that a desiccant is bonded to the scraped region by an adhesive.
• Since the organic compound film and the[0071]second electrode105 of the organic light-emittingelement106 are provided along the side faces of the first insulatingfilm107, the laminate film constituting the light-emittingelement106 is not broken even if the stress is externally applied onto thesecond substrate101. Moreover, since the first insulatingfilm107 and the secondinsulating film108 made of an elastic organic resin film are provided on the TFT in the pixel portion and the TFT in the driving circuit portion, the TFTs in the driving circuit portion and the pixel portion are not damaged even if the stress is externally applied onto thesecond substrate101.
• A chain line A-A′ indicates a cross section of the[0072]pixel portion121 and the peripheral area of thefirst substrate100; a chain line B-B′ shows a connection structure between thesecond electrode105 and thewiring124 connected to the external input terminal; and a chain line C-C′ shows a connection structure between the FT1 in the driving circuit portion and the external input terminal.
• FIG. 6 is a top plan view of this embodiment mode. FIG. 6 shows the appearance of a display device using an organic light-emitting element according to the present invention. The cross-sections cut along the chain lines A-A′, B-B′, and C-C′ in FIG. 6 correspond to the chain lines A-A′, B-B′, and C-C′ in FIG. 1, respectively. The same elements as those in FIG. are designated by the same reference numerals in FIG. 6.[0073]
• The top plan view of FIG. 6 shows the[0074]first substrate100 and thesecond substrate101 having light transmittance, which are bonded to each other through the adhesive102. On thefirst substrate100, thepixel portion121, the driving circuit portion, a flexible printed circuit (FPC)200, thewirings122 and124 serving as external input terminals for attaching theFPC200 onto the substrate, and the like are formed.
• As the driving circuit portion, a first gate wiring side[0075]driving circuit portion120aand a second gate wiring sidedriving circuit portion120bare respectively provided on the ends of the gate wiring in the pixel portion so as to be connected to the gate wiring in the pixel portion. A source wiring sidedriving circuit portion120cis provided so as to be connected to a source wiring in the pixel portion.
• The[0076]FPC200 is bonded to theexternal input terminal122 through an anisotropic conductive resin. The firstinsulating film107 serving as the bank is provided in a column direction in a striped manner. The secondinsulating film108 is provided in a closed curve form in the peripheral area of thefirst substrate100 so as to cover the first gate wiring sidedriving circuit portion120a, the second gate wiring sidedriving circuit portion120b, and the source wiring sidedriving circuit portion120c. Thesecond electrode105, serving as a common electrode, is provided in a striped manner along the first insulatingfilm107 and is short-circuited outside the pixel portion.
• The display device using the organic light-emitting element manufactured as described above can be used as a display section of various electronic appliances.[0077]
• (Embodiment Mode 2)[0078]
• Embodiment Mode 2 will be described with reference to a cross-sectional view of FIG. 2. FIG. 2 is a cross-sectional view showing an active-matrix organic light-emitting element of Embodiment Mode 2. In Embodiment Mode 2, the display device described in Embodiment Mode 1, whose periphery is further covered with an adhesive and a[0079]metal plate127 having a U-shaped cross section so as to prevent water from entering the organic light-emitting element, is described.
• With the reference to the top plan view of FIG. 6, the adhesive and the[0080]metal plate127 are placed so as not to overlap thepixel portion121. In the region where theexternal input terminal122 is formed so as to attach theFPC200 thereto, the side face of thefirst substrate100 and the side face of thesecond substrate101 are separate from each other by 5 to 20 mm. Therefore, the adhesive and themetal plate127 are provided in the periphery of the region where the end of thefirst substrate100 and the end of thesecond substrate101 overlap with each other except the above-mentioned region.
• In Embodiment Mode 2, the[0081]metal plate127 is formed to have a U-shape. Themetal plate127 is intentionally omitted on thepixel portion121, which occupies a dominant area on the external front face of the display device, and the back face of thepixel portion121. The reason for this is as follows. When the display device is made to be thinner, the strength of thefirst substrate100 and thesecond substrate101 is correspondingly lowered. In order to prevent the cracking from being generated in thefirst substrate100 and thesecond substrate101 by a sudden change in the temperature of the environment where the display device is used due to the difference in thermal expansion coefficient of themetal plate127, thefirst substrate100 and thesecond substrate101, the overlapping area of the first substrate, the second substrate and the metal substrate is limited.
• According to Embodiment Mode 2, a[0082]first adhesive125 for bonding thefirst substrate100 and thesecond substrate101 to each other and asecond adhesive126 provided between theU-shaped metal plate127 and the side face of the display device are provided in contact with each other. As a result, the water vapor contained in the outside air is prevented from passing through the side face of the display device to enter the sealed region. Thus, water can be prevented from entering the organic light-emitting element placed in thepixel portion121, in a low-cost and simple manner.
• In Embodiment Mode 2, it is also possible to fill the[0083]second adhesive126 placed between themetal plate127 and the side face of the display device with a desiccant.
• (Embodiment Mode 3)[0084]
• Embodiment Mode 3 will be described with reference to a cross-sectional view of FIG. 3. FIG. 3 is a cross-sectional view showing an active-matrix organic light-emitting element according to Embodiment Mode 3. The differences from Embodiment Mode 1 will be described.[0085]
• The thicknesses and the materials of the base films, the semiconductor film, the gate insulating film, the gate electrodes, and the first interlayer insulating film are the same as those in Embodiment Mode 1.[0086]
• In Embodiment Mode 3, the second[0087]interlayer insulating film115 formed of an organic resin film is thermally cured at 200 to 300° C. A resist is formed on the upper face of the secondinterlayer insulating film115, and is then etched by using a reactive gas. After formation of a contact hole reaching thesemiconductor film110, the resist is removed. The surface of the secondinterlayer insulating film115 is treated with a plasma using argon or nitrogen as a reactive gas. The reactive gas causes the molecular dissociation by plasma discharge decomposition to generate excited molecules, radicals and ions to be reacted with the secondinterlayer insulating film115. As a result, the quality of the surface of the secondinterlayer insulating film115 is improved to refine its surface. As the secondinterlayer insulating film115, any one of an acrylic resin film, a polyimide resin film, and a polyamide resin film may be used. In this embodiment mode, an acrylic resin film is used.
• The[0088]first electrode103 is provided on the secondinterlayer insulating film115 as a cathode of the organic light-emitting element. The cathode may be made of a known material such as MgAg or AlLi to have a thickness of 100 nm to 200 nm. Since the surface of the secondinterlayer insulating film115 is refined, an impurity contained in the secondinterlayer insulating film115 is prevented from being diffused to thefirst electrode103 serving as the cathode of the organic light-emitting element.
• Next, the[0089]drain electrode116 is formed to have a thickness of 400 nm so as to overlap the end of thefirst electrode103. Thesource electrode117, theconductor film123 and thewirings122 and124 are formed of the same layer as thedrain electrode116. Next, an insulating film made of an organic material is formed to have a thickness of 1 to 10 μm, and is patterned to form the first insulatingfilm107 and the secondinsulating film108. In this embodiment mode, a photosensitive acrylic resin film having a thickness of 3 μm is used as the insulating film. The firstinsulating film107 made of an organic resin is provided in a striped manner as a bank so as to cover the end of thefirst electrode103. The secondinsulating film108 is provided in the peripheral area of thefirst substrate100. The firstinsulating film107 and the secondinsulating film108 are treated with a plasma, using argon or nitrogen as a reactive gas, thereby forming a fine and hard film on the surface of each insulating film.
• Next, the[0090]organic compound film104 is provided on thefirst electrode103. A known material may be used for theorganic compound film104. Next, thesecond electrode105 formed of a transparent conductive film is provided on theorganic compound film104 as an anode. An ITO film may be used for the anode. The deposition of the first electrode, the organic compound film and the second electrode completes the organic light-emittingelement106.
• Then, a DLC film having a thickness of 100 nm is provided as the[0091]protective film109 so as to cover the second electrode, the first insulating film and the second insulating film of the organic light-emittingelement106.
• Moreover, a gap between the[0092]first substrate100 and thesecond substrate101 is filled with afirst adhesive129, whereby water and oxygen contained in the outside air can be prevented from entering the organic light-emittingelement106 through the side faces of the display device. Since thefirst adhesive129 used in this embodiment mode is also provided above the organic light-emittingelement106, it is necessary to sufficiently conduct the degassing and dehydration under vacuum. Thefirst adhesive129 is provided above thefirst substrate100, and thesecond substrate101 is provided so as to be opposed to thefirst substrate100. Then, the stress is applied under vacuum so as to press the twosubstrates100 and101 against one another, thereby curing thefirst adhesive129. In the step of forming the layers from the base films to the protective film, even if the thickness of the laminate film in the driving circuit portion, the pixel portion and the peripheral area of thefirst substrate100 slightly differs, the difference in thickness is absorbed by the adhesive129 by providing the adhesive129 on the laminate film.
• Since the[0093]first adhesive129 used in this embodiment mode is provided even above the organic light-emitting element, it is necessary to sufficiently conduct the degassing and dehydration under vacuum. Adesiccant128 in a granular form is dispersed in thefirst adhesive129. The finely ground desiccant, i.e., having a diameter of 1.0 μm or less, preferably, 0.2 μm or less, more preferably, 0.1 μm or less, is used so as not to generate the unevenness in the gap between thefirst substrate100 and thesecond substrate101. As thedesiccant128, calcium oxide, barium oxide or the like may be used. Since thedesiccant128 is provided in the proximity of the organic light-emittingelement106, the concentration of water in the vicinity of the organic light-emitting element can be lowered to prolong the lifetime of the display device.
• In the case where light emitted from the organic light-emitting[0094]element106 is to be obtained from the side of the sealing substrate (second substrate)101, it is preferred to use barium oxide, which has a higher transparence than that of calcium oxide.
• Next, in the same manner as Embodiment Mode 2, a[0095]second adhesive130 is provided between theU-shaped metal plate127 and the side faces of the display device so as to prevent water from passing through the side faces of the display device. This embodiment mode differs from Embodiment Mode 2 in that thedesiccant128 is also dispersed in thesecond adhesive130. Before entering the sealed region between the element substrate and the sealing substrate, water contained in the outside air is captured by thehygroscopic desiccant128 dispersed in thesecond adhesive130. As a result, the lifetime of the display device can be intended to be prolonged. For example, dark spots due to the reaction between the cathode of the organic light-emitting element and water can be prevented from being generated.
• In this embodiment mode, since a fine film is formed on the second[0096]insulating film108, water passing through theprotective film109 can be prevented from further passing through the side faces of the secondinsulating film108 to enter the organic light-emitting element.
• In Embodiment Mode 3, since the anode formed of a transparent conductive film is on the side of the[0097]second substrate101 whereas the cathode having light reflectance is on the side of thefirst substrate100, light emitted from the organic light-emittingelement106 can be output from the side of thesecond substrate101 made of glass. The light emitted from the organic light-emittingelement106 is externally obtained fromsecond substrate101 through the adhesive. Therefore, the obtained light appears as interference fringes if the gap between the first substrate and the second substrate in the pixel portion is not uniform. If the distance between the substrates in the pixel portion differs from that in the peripheral area of the first substrate, the distance between the substrates gradually varies from the peripheral area to the pixel portion to generate the interference fringes in the pixel portion. Thus, in order to uniform the distance between the substrates in the pixel portion, it is necessary to equalize the distance between the substrates in the peripheral area of the first substrate with that in the pixel portion. According to the present invention, even if the total thickness of the laminate layer on thefirst substrate100 slightly varies in the pixel portion, the driving circuit portion, and the peripheral area of the first substrate, the variation in thickness of the laminate film is absorbed by the first adhesive. As a result, the distance between the first substrate and the second substrate can be made uniform throughout the peripheral area of the first substrate, the driving circuit portion, and the pixel portion.
• (Embodiment Mode 4)[0098]
• Embodiment Mode 4 will be described with reference to a cross-sectional view of FIG. 4. FIG. 4 is a cross-sectional view showing an active matrix organic light-emitting element according to Embodiment Mode 4.[0099]
• The thicknesses and the materials of the base films, the semiconductor film, the gate insulating film, the gate electrodes, the first interlayer insulating film, and the second interlayer insulating film are the same as those in Embodiment Mode 1.[0100]
• The[0101]drain electrode116 is formed so as to overlap the end of thefirst electrode103. Then, a photosensitive polyimide resin film having a thickness of 2.0 μm is formed and patterned into the first insulatingfilm107 and the secondinsulating film108. The firstinsulating film107 made of an organic resin is provided in a striped manner as a bank so as to cover the end of thefirst electrode103. The secondinsulating film108 is provided in the peripheral area of thefirst substrate100.
• Next, a photosensitive organic resin film is formed to have a thickness of 0.1 to 10 μm. Then, the photosensitive organic resin film is patterned and cured at 200 to 300° C. to form a convex-shaped third[0102]insulating film134 as a spacer on the upper surface of the bank (first insulating film). A polyimide resin film or an acrylic resin film can be used as the photosensitive organic resin film; in this embodiment mode, an acrylic resin film is used. In this embodiment mode, spacers are also formed on the upper face of the secondinsulating film108, for example, in thedriving circuit portion120 and the peripheral area of thefirst substrate100. The spacer provided in the peripheral area of thefirst substrate100 is formed to have a closed curve form.
• Next, the[0103]organic compound film104 is provided on thefirst electrode103. A known material may be used for theorganic compound film104. Next, thesecond electrode105 formed of a transparent conductive film is provided on theorganic compound film104 as an anode. An ITO film may be used for the anode.
• Then, the[0104]protective film109 formed of a DLC film having a thickness of 80 nm is provided so as to cover the anode, the bank, the second insulating film, and the spacers of the organic light-emitting element. Theprotective film109, which serves to prevent water from entering inside, is formed on the side faces of the spacer. Thus, if a plurality of spacers having a closed curve form are provided in the peripheral area of thefirst substrate100, water passing through the side faces of the display device is blocked for a plurality of times by theprotective film109 provided on the side faces of the spacers. As a result, the amount of water entering the display device through its side faces can be reduced.
• Next, the adhesive[0105]102 is provided in the peripheral area of thefirst substrate100. A gap between the spacer having a closed curve form provided in the peripheral area of thefirst substrate100 and another spacer having a closed curve form provided inside the aforementioned spacer is filled with the adhesive102. Thesecond substrate101 made of glass, which is used as the sealing substrate, is bonded to theelement substrate100 through the adhesive102.
• In this embodiment mode, since the anode formed of a transparent conductive film is on the side of the[0106]second substrate101 whereas the cathode having light reflectance is on the side of thefirst substrate100, light emitted from the organic light-emitting element can be output from the side of thesecond substrate101 made of glass. When the light emitted from the organic light-emitting element is output from the side of thesecond substrate101, the obtained light appears as interference fringes to degrade the display quality if the gap between the first substrate and the second substrate in the pixel portion is not uniform. With the spacers being placed in the pixel portion, the driving circuit portion and the peripheral area as described in this embodiment mode, the uniformity of the gap between the first substrate and the second substrate is improved to enable the manufacturing of a display device with good display quality.
• FIG. 7 is a top plan view of this embodiment mode. FIG. 7 shows the arrangement of convex-shaped third[0107]insulating films131 serving as spacers in this embodiment mode. On the first insulatingfilm107 in thepixel portion121, the spacers having a circular cross section are placed at equal intervals in the horizontal and vertical directions of thepixel portion121. The spacers having a circular cross section are placed at equal intervals on the secondinsulating film108 situated above the first gate wiring sidedriving circuit portion120a, the second gate wiring sidedriving circuit portion120band the source wiringside driving circuit120c. In the peripheral area of thefirst substrate100, thespacers131 are placed in a closed curve form on the secondinsulating film108. In FIG. 7, thespacers131 having a closed curve form are formed in a double line. However, thespacers131 can be formed in a triple or quadruple line; it can be appropriately designed by the designer.
• Although not shown, the surface of the sealing substrate or the element substrate may be scraped off by using a sandblast method to form a convex portion where the desiccant is to be placed. It is also possible to place an adhesive in the convex portion so as to fix the desiccant thereto. In this way, the desiccant is fixed through the adhesive to prevent the desiccant from moving.[0108]
• (Embodiment Mode 5)[0109]
• Embodiment Mode 5 will be described with reference to a cross-sectional view of FIG. 5. FIG. 5 is a cross-sectional view showing an active matrix organic light-emitting element of Embodiment Mode[0110]5.
• In Embodiment Mode[0111]5, thegate insulating film111, the firstinterlayer insulating film114, the secondinterlayer insulating film115 and the insulating films are etched to form an opening. It is preferred to set a depth of the opening to 3 to 15 μm. After formation of theprotective film109 as the uppermost layer of thefirst substrate100, thesecond adhesive132, in which thedesiccant128 is dispersed, is provided in the opening covered with theprotective film109. As thedesiccant128, calcium oxide or barium oxide can be used; in this embodiment mode, barium oxide is used. A syringe is filled with thesecond adhesive132, in which thegranular desiccant128 having a diameter of 0.3 to 1.0 μm is dispersed, by a known dispenser system. A gas pressure of a predetermined value is applied onto the upper end of the syringe so that the adhesive132 and thedesiccant128 are ejected through a narrow nozzle on the lower end of the syringe toward the opening. Thesecond adhesive132 are fully subjected to degassing and dehydration before use.
• Next, the[0112]first adhesive131 is applied onto the peripheral area of thefirst substrate100 by a known dispenser system, so that thefirst substrate100 and thesecond substrate101 are bonded to each other under dry air. As dry air, nitrogen or argon, which is an inert gas, is used.
• In this embodiment mode, the insulating films such as the second interlayer insulating film and the second insulating film are patterned to provide a region where the desiccant is to be placed. Since water passing from the side faces of the display device through the adhesive is captured by the[0113]hygroscopic desiccant128 before reaching the organic light-emitting element, it is possible to prevent the generation of dark spots due to the reaction between water and the cathode of the organic light-emitting element and the peeling of the cathode and the organic compound film.
• In this embodiment mode, the insulating film formed of a photosensitive organic resin film is patterned to simultaneously form the first insulating film (bank)[0114]107, the secondinsulating film108 provided in the peripheral area of thefirst substrate100, and a thirdinsulating film133 branching off from the secondinsulating film108.
• FIG. 8 is a top plan view of Embodiment Mode 5. The insulating film formed of a photosensitive organic resin film is patterned to form the first insulating[0115]film107, the secondinsulating film108, and the thirdinsulating film133. The firstinsulating film107 is formed in a striped manner in thepixel portion121 on thefirst substrate100. In the peripheral area of thefirst substrate100, the secondinsulating film108 is formed in a closed curve form so as to cover the first gate wiring sidedriving circuit portion120a, the second gate wiring sidedriving circuit portion120b, and the source wiring sidedriving circuit portion120c. The thirdinsulating film133 branches off from the secondinsulating film108. Thedesiccant128 is provided in the gap between the thirdinsulating film133 and the secondinsulating film108. Since thedesiccant128 is fixed through the adhesive, thedesiccant128 can be prevented from moving. The cross-sections cut along the chain lines D-D, E-E′ and F-F′ in the top plan view of FIG. 8 are shown in FIG. 5. The same elements as those in FIG. 5 are designated by the same reference numerals in FIG. 8.
• Embodiments[0116]
• (Embodiment 1)[0117]
• The present invention is applicable to any display devices using the organic light[0118]5 emitting element. FIG. 10 shows an example of such display devices, illustrating an active-matrix display device manufactured by using TFTs. The TFTs in Embodiments are sometimes classified into amorphous silicon TFTs and polysilicon TFTs, depending on the material of a semiconductor film forming a channel formation region. The present invention is applicable to either of them if the channel formation region has a sufficiently high mobility.
• An n-[0119]channel type TFT431 and a p-channel type TFT432 are formed in adriving circuit portion437. ATFT433 for switching, aTFT434 for reset, aTFT436 for current control and astorage capacitor435 are formed in apixel portion438.
• As a[0120]substrate401, a substrate made of glass such as quartz, barium borosilicate glass as is represented by #7059 glass and #1737 glass manufactured by Corning Inc., or alumino borosilicate glass, is used.
• Next, a base film[0121]402 formed of a silicon oxide film, a silicon nitride film or a silicon nitride oxide film is provided. For example, a siliconnitride oxide film402amade of SiH₄, NH₃and N₂O is formed to have a thickness of 10 to 200 nm (preferably, 50 to 100 nm) by a plasma CVD method. In the same manner, a silicon nitride oxide film402bmade of SiH₄and N₂O is deposited thereon to have a thickness of 50 to 200 nm (preferably, 100 to 150 nm). Although the base film402 is shown as a double-layered structure, the base film402 may be formed as a single-layer film of the above-described insulating film or a multi-layered structure including two or more layers.
• Next, island-like semiconductor layers[0122]403 to407, agate insulating film408, andgate electrodes409 to412 are formed. Each of the island-like semiconductor layers403 to407 has a thickness of 10 to 150 nm, the gate insulating film has a thickness of 50 to 200 nm, and each of the gate electrodes has a thickness of 50 to 800 nm.
• Next, an[0123]interlayer insulating film413 consisting of an insulating film made of an inorganic material such as silicon nitride or silicon nitride oxide and an insulating film made of an organic material such as acrylic or polyimide is formed. A thickness of theinterlayer insulating film413 may be set to 1 to 3 μm. The insulating film made of an organic material is desired to have a sufficient thickness to level the unevenness produced due to the island-like semiconductor films403 to407 and thegate electrode409 to412.
• Next, a[0124]cathode423 of the organic light-emitting element is formed. For thecathode423, a material such as MgAg or LiF may be used. A thickness of thecathode423 may be set to 100 to 200 nm.
• Subsequently, a conductive film containing aluminum as a main component is formed to have a thickness of 1 to 5 μm and then is etched. As a result, a[0125]data wiring418, adrain side wiring419, apower supply wiring420 and adrain side electrode421 are formed in the pixel portion. Thedata wiring418 is connected to the source side of theTFT433 for switching while, although not shown, thedrain side wiring419 connected to the drain side of theTFT433 for switching is connected to thegate electrode411 of theTFT436 for current control,. The source side of theTFT436 for current control is connected with thepower supply wiring420. Thedrain side electrode421 is provided so as to connect the drain side of theTFT436 for current control with thecathode423. In thedriving circuit portion437, thewirings414 and416 are connected to the island-like semiconductor film403 of the n-channel type TFT431, whereas thewirings415 and417 are connected to the island-like semiconductor film404 of the p-channel type TFT432.
• Next, a photosensitive acrylic resin film is formed to have a thickness of 1 to 10 μm, and then is etched. As a result, a bank formed of the first insulating film is formed in the[0126]pixel portion438 so as to cover thewirings414 to417. The bank is formed so as to cover the end of thecathode423, thereby preventing thecathode423 and theanode425 from short5 circuiting in this portion. A secondinsulating film429 is formed in thedriving circuit portion437 and the peripheral area of thesubstrate401.
• Then, an organic resin film such as an acrylic resin film is patterned to form a column-[0127]like spacer430 at a desired position for maintaining the distance between the substrates. In this embodiment, a column-like spacer having a height of 1 μm is provided in thepixel portion438.
• Next, an[0128]organic compound film424 of the organic light-emitting element is formed. Theorganic compound film424 is formed to have a single-layered or a multi-layered structure; a higher luminous efficiency can be obtained with a multi-layered structure. Generally, theorganic compound film424 is deposited on theanode425 in the order of: hole injection layer/hole transport layer/light emitting layer/electron transport layer. However, theorganic compound film424 may have a structure of: hole transport layer/light emitting layer/electron transport layer; or hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer. In the present invention, any conventional structures may be used.
• In Embodiment 1, color display is performed by vapor-deposition of three light emitting layers corresponding to RGB. As specific examples of light emitting layers, the following may be used as the respective layers: as a layer emitting red light, cyanopolyphenylene; as a layer emitting green light, polyphenylene vinylene; and as a layer emitting blue light, polyphenylene vinylene or polyalkylphenylene. A thickness of the light emitting layer may be set to 30 to 150 nm. The above examples are merely some examples of the organic compounds that can be used as the light emitting layers, and thus the organic compounds are not limited thereto.[0129]
• The organic compound film described in Embodiment[0130]1 has a laminate structure including a light emitting layer and a hole injection layer made of PEDOT (polythiophen) or PAni (polyaniline).
• Next, the[0131]anode425 made of ITO (Indium Tin Oxide) is formed. In the above-described manner, the organic light-emitting element including the cathode made of a material such as MgAg or LiF, the organic compound film formed by the laminate of the light emitting layer and the hole transport layer, and the anode made of ITO is provided. By using a transparent electrode as the anode, light can be emitted in the direction indicated by the arrow in FIG. 10.
• A[0132]DLC film439 is formed on the entire surface area of thefirst substrate401 so as to prevent water vapor or oxygen from passing through the sealed portion to deteriorate the organic light-emitting element. TheDLC film439 is formed on the entire surface except the external input terminal. When the DLC film is to be formed, the external input terminal may be covered with a masking tape or a shadow mask in advance.
• An adhesive is applied onto the second[0133]insulating film429, so that the second substrate having light transmittance is bonded to the first substrate under vacuum. Since the thickness of the adhesive is determined by the height of the column-like spacer430 provided in the pixel portion, the distance between the substrate and the sealing substrate is adjusted so as to be uniform from the pixel portion to the peripheral area of the substrate.
• FIG. 9 is a top plan view of the pixel portion shown in the cross-sectional view of FIG. 10. The same elements as those in FIG. 10 are designated by the same reference numerals in FIG. 9. The cross-sections corresponding to the chain lines G-G′ and H-H′ in FIG. 9 are shown in FIG. 10. A bank is provided outside the region surrounded by a dot line. Within the region surrounded by the dot line, light emitting layers which emit light of colors corresponding to RGB pixels and an anode are provided. The layout of the pixel portion shown in the top plan view of FIG. 9 is applicable to that of the pixel portion of the display device in Embodiment Mode 4. Moreover, the layout of the pixel portion shown in the top plan view of FIG. 9, from which the column-like spacer is omitted, is applicable to that of the pixel portion of the display device in Embodiment Modes 1 to 4.[0134]
• FIG. 11 illustrates an equivalent circuit of such a pixel portion, in which the same elements as those in FIG. 10 are designated by the same reference numerals. The[0135]TFT433 for switching has a multi-gate structure. An LDD overlapping with the gate electrode is provided for theTFT436 for current control. The TFT using polysilicon demonstrates high operation speed. Accordingly, the deterioration such as hot carrier injection is likely to occur for such a TFT. For this reason, it is very effective to form TFTs having different structures (the TFT for switching having a sufficiently low OFF current and the TFT for current control having resistance against hot carrier injection) depending on their functions in the pixel so as to manufacture the display device with high reliability, capable of performing good image display (having high operation performance).
• Even after the[0136]TFT433 for switching in a conductive state is switched to be in a non-conductive state, it is effective to provide a storage capacitor (condenser)435 so as to obtain the display with high brightness by holding theTFT436 for current control in a conductive state to maintain the light emitted from the organic light-emitting element.
• Furthermore, in a time-division gray-scale system in which gray-scale display is performed by varying the time period of light emission of the organic light-emitting[0137]element426, theTFT434 for reset is brought into a conductive state so as to switch the organic light-emitting element from a light emission state to a non-light emission state, thereby controlling the time period of light emission of the organic light-emittingelement426.
• In Embodiment 1, it is possible to disperse a granular desiccant having a diameter of 0.2 to 0.5 μm in the adhesive. As a result, the amount of water entering the display device through its side faces can be reduced.[0138]
• (Embodiment 2)[0139]
• In Embodiment 2, mother substrates (mother glasses), the area of each mother substrate corresponding to the total area of a plurality of unit panels, are bonded to each other. When the mother substrates are cut into individual panels, a CO[0140]₂laser is used as cutting means.
• A CO[0141]₂laser employs carbon dioxide as a reactive medium, and is operated by exciting carbon dioxide to be in an inverted population state. Since the CO₂laser generates light having a wavelength in an infrared region (10.6 nm), the object irradiated with laser light can be heated.
• A method of cutting a glass substrate using a CO[0142]₂laser will be described with reference to a perspective view of FIG. 14. FIG. 14 is a perspective view showing a method of cutting aglass substrate501 irradiated with laser, of theglass substrates501 and502 that are bonded to each other. An ellipsoidallaser beam spot503 is radiated onto theglass substrate501 moving in the direction indicated by the arrow by anoptical system504 for performing laser radiation. A refrigerant is sprayed by anozzle507 onto the site (cooled site506) in the rear of thebeam spot503. In this way, the site heated by the laser radiation is subsequently cooled in a quick manner to generate a thermal strain in theglass substrate501. As a result, theglass substrate501 is cut along alaser radiation line505.
• As an apparatus for cutting a glass substrate with a CO[0143]₂laser, a laser scriber manufactured by Mitsuboshi Diamond Industrial Co. Ltd. can be used. Two mother substrates may be simultaneously cut, or may be cut one by one. It is preferred to cut two mother substrates at a time because the tact of the manufacturing steps is improved to increase the productivity.
• By radiating a CO[0144]₂laser onto the surface of the glass substrate, the generation of waste by cutting the glass substrate can be restrained to prevent defects from occurring. Moreover, since a method of cutting the substrates with a CO₂laser employs both the laser radiation and the spray of a cooling medium, the impact on the substrate is small. As a result, even with a thin mother substrate, it is possible to cut the glass substrate at a high yield.
• (Embodiment 3)[0145]
• A light-emitting device formed by implementing the present invention can be incorporated to various electric-equipment, and a pixel portion is used as an image display portion. Given as such electronic equipment of the present invention are cellular phones, PDAs, electronic books, video cameras, lap-top computers, and image play back devices with the recording medium, for example, DVD (digital versatile disc), digital cameras, and the like. Specific examples of those are shown in FIGS. 12A to[0146]13C.
• FIG. 12A shows a cellular phone, which is composed of a[0147]display panel9001, anoperation panel9002, and a connectingportion9003. Thedisplay panel9001 is provided with adisplay device9004, anaudio output portion9005, anantenna9009, etc. Theoperation panel9002 is provided withoperation keys9006, apower supply switch9007, anaudio input portion9008, etc. The present invention is applicable to thedisplay device9004.
• FIG. 12B shows a mobile computer, or a portable information terminal, which is composed of a[0148]main body9201, acamera portion9202, animage receiving portion9203, operation switches9204, and adisplay device9205. The present invention can be applied to thedisplay device9205. In such electronic devices, the display device of 3 to 5 inches is employed, however, by employing the display device of the present invention, the reduction of the weight in the portable information terminal can be attained.
• FIG. 12C shows a portable book, which is composed of a[0149]main body9301,display devices9302 to9303, and amemory medium9304, anoperation switch9305, and anantenna9306, and which displays the data recorded in MD or DVD and the data received by the antenna. The present invention can be applied to thedisplay devices9302 to9303. In the portable book, the display device of the 4 to 12 inches is employed. However, by employing the display device of the present invention, the reduction of the weight and thickness in the portable book can be attained.
• FIG. 12D shows a video camera, which is composed of a[0150]main body9401, adisplay device9402, anaudio input portion9403, operation switches9404, abattery9405, animage receiving portion9406, and the like. The present invention can be applied to thedisplay device9402.
• FIG. 13A shows a personal computer, which is composed of a[0151]main body9601, animage input portion9602, adisplay device9603, and akey board9604. The present invention can be applied to thedisplay device9603.
• FIG. 13B shows a player employing a recording medium with programs recorded thereon (hereinafter referred to as recording medium), which is composed of a[0152]main body9701, adisplay device9702, aspeaker portion9703, arecording medium9704, and anoperation switch9705. The device employs DVD (digital versatile disc), CD, etc. as the recording medium so that music can be listened, movies can be seen and games and Internet can be done. The present invention can be applied to thedisplay device9702.
• FIG. 13C shows a digital camera, which is composed of a[0153]main body9801, adisplay device9802, aneyepiece portion9803, anoperation switch9804, and an image receiving portion (not shown). The present invention can be applied to thedisplay device9802.
• The display device of the present invention is employed in the cellular phones in FIG. 12A, the mobile computer or the portable information terminal in FIG. 12B, the portable book in FIG. 12C, and the personal computer in FIG. 13A. The display device can reduce the power consumption of the above device by displaying the black background in a standby mode.[0154]
• In the operation of the cellular phone shown in FIG. 12A, luminance is lowered when the operation keys are used, and the luminance is raised after usage of the operation switch, whereby the low power consumption can be realized. Further, the luminance of the display device is raised at the receipt of a call, and the luminance is lowered during a call, whereby the low power consumption can be realized. Besides, in the case where the cellular phone is continuously used, the cellular phone is provided with a function of turning off a display by time control without resetting, whereby the low power consumption can be realized. Note that the above operations may be conducted by manual control.[0155]
• The present invention can be applied to the display device which is employed in a navigation system, a refrigerator, a washing machine, a micro-wave oven, a telephone, a fax machine, etc. As described above, the applicable range of the present invention is so wide that the present invention can be applied to various products.[0156]
• According to the present invention, since the element substrate and the sealing substrate can be provided in the proximity, the amount of water entering the display device through its side face can be reduced.[0157]
• On the first substrate having the light-emitting element provided thereon, the total thicknesses of the layers deposited in the peripheral area of the first substrate, the pixel portion and the driving circuit portion are equalized with each other. Then, the adhesive is provided as thin as possible in the peripheral area of the first substrate so as to bond a second substrate to the first substrate. As a result, the distance between the first substrate and the second substrate can be made uniform throughout the peripheral area of the first substrate, the pixel portion and the driving circuit portion. More desirably, if the thickness of the laminate film deposited in the peripheral area of the first substrate is reduced by the thickness of the adhesive provided in the peripheral area of the first substrate, the distance between the first substrate and the second substrate can be made uniform throughout the peripheral area of the first substrate, the pixel portion and the driving circuit portion. To achieve this uniformity, it is recommended that among the layers deposited in the pixel portion, at least the second interlayer insulating film having a dominant thickness and the second insulating film formed of the same layer as the bank are formed below the adhesive.[0158]
• Moreover, since the protective film for the organic light-emitting element is also provided on the side faces of the laminate film in the peripheral area of the first substrate, water can be prevented from entering the display device through its side faces.[0159]

Claims (71)

What is claimed is:

1. A display device comprising:

a first electrode formed over a first substrate;

a first insulating film formed so as to cover an end of the first electrode;

a light-emitting organic compound film over the first electrode and in contact with a side face of the first insulating film;

a second electrode formed over the light-emitting organic compound film;

a second insulating film formed over a periphery of the first substrate;

an adhesive layer formed on the second insulating film;

a second substrate in contact with the adhesive layer; and

a light-emitting element comprising the light-emitting organic compound film interposed between the first electrode and the second electrode,

wherein the first insulating film and the second insulating film comprise a same material.

2. A display device comprising:

a first electrode formed over a first substrate;

a first insulating film formed so as to cover an end of the first electrode;

a light-emitting organic compound film over the first electrode and in contact with a side face of the first insulating film;

a second electrode formed over the light-emitting organic compound film;

a second insulating film formed over a periphery of the first substrate; and

a second substrate provided so as to overlap the first insulating film and the second insulating film; and

a light-emitting element comprising the light-emitting organic compound film interposed between the first electrode and the second electrode,

wherein the first insulating film and the second insulating film comprise a same material, and

wherein a gap between the first substrate and the second substrate is filled with an adhesive layer.

3. A display device according toclaim 1, wherein the second insulating film has a width of 100 to 5000 μm.

4. A display device according toclaim 2, wherein the second insulating film has a width of 100 to 5000 μm.

5. A display device according toclaim 1, wherein a protection layer covering the second electrode, the first insulating film and the second insulating film is provided.

6. A display device according toclaim 2, wherein a protection layer covering the second electrode, the first insulating film and the second insulating film is provided.

7. A display device according toclaim 5, wherein the first substrate and the second substrate comprise glass.

8. A display device according toclaim 6, wherein the first substrate and the second substrate comprise glass.

9. A display device according toclaim 1, wherein a gap between the first substrate and the second substrate is filled with an inactive gas or a nitrogen gas.

10. A display device according toclaim 2, wherein a gap between the first substrate and the second substrate is filled with an inactive gas or a nitrogen gas.

11. A display device according toclaim 1, wherein the adhesive layer has a thickness of 0.05 to 0.5 μm.

12. A display device according toclaim 2, wherein the adhesive layer has a thickness of 0.05 to 0.5 μm.

13. A display device according toclaim 1, wherein the first insulating film has a thickness of 1.0 to 10 μm.

14. A display device according toclaim 2, wherein the first insulating film has a thickness of 1.0 to 10 μm.

15. A display device according toclaim 1, wherein the second insulating film has a thickness of 1.0 to 10 μm.

16. A display device according toclaim 2, wherein the second insulating film has a thickness of 1.0 to 10 ηm.

17. A display device according toclaim 1, wherein the first insulating film comprises any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

18. A display device according toclaim 2, wherein the first insulating film comprises any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

19. A display device comprising:

a first electrode formed over a first substrate;

a first insulating film formed so as to cover an end of the first electrode; and

a second insulating film provided in a convex manner on an upper face of the first insulating film,

a light-emitting element comprising a light-emitting organic compound film interposed between the first electrode and a second electrode.

20. A display device comprising:

a first electrode formed over a first substrate;

a first insulating film formed so as to cover an end of the first electrode;

a light-emitting organic compound film over the first electrode and in contact with the first insulating film;

a second electrode formed over the light-emitting organic compound film;

a second insulating film formed over a periphery of the first substrate;

a third insulating film provided in a convex manner on an upper face of the first insulating film;

an adhesive layer formed over the second insulating film; and

a second substrate in contact with the adhesive layer,

a light-emitting element comprising the light-emitting organic compound film interposed between the first electrode and the second electrode.

21. A display device according toclaim 20, wherein the first insulating film and the second insulating film comprise a same material.

22. A display device according toclaim 20, wherein the second insulating film has a width of 100 to 5000 μm.

23. A display device according toclaim 20, wherein a protection layer covering the second electrode, the first insulating film, the second insulating film and the third insulating film is provided.

24. A display device according toclaim 23, wherein the protective layer is in contact with an external input terminal.

25. A display device according toclaim 23, wherein the first substrate and the second substrate comprise glass.

26. A display device according toclaim 20, wherein a gap between the first substrate and the second substrate is filled with an inert gas or a nitrogen gas.

27. A display device according toclaim 20, wherein the adhesive layer has a thickness of 0.05 to 0.5 μm.

28. A display device according toclaim 20, wherein the first insulating film has a thickness of 1.0 to 10 μm.

29. A display device according toclaim 20, wherein the second insulating film has a thickness of 1.0 to 10 μm.

30. A display device according to20, wherein the third insulating film has a thickness of 0.2 to 10 μm.

31. A display device according toclaim 19, wherein the second insulating film comprises any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

32. A display device according toclaim 20, wherein the second insulating film comprises any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

33. A display device comprising:

a first electrode over a first substrate;

a first insulating film provided so as to cover an end of the first electrode;

a light-emitting organic compound film over the first electrode and in contact with a side face of the first insulating film;

a second electrode over the light-emitting organic compound film;

a light-emitting element comprising the light-emitting organic compound film interposed between the first electrode and second electrode;

a second insulating provided in a periphery of the first substrate;

a third insulating film provided along the second insulating film and interposed between the first insulating film and the second insulating film;

a desiccant provided in a gap between the second insulating film and the third insulating film.

34. A display device according toclaim 33, further comprising an adhesive layer above the second insulating film, wherein the adhesive layer is in contact with the second substrate.

35. A display device according toclaim 33, wherein the first insulating film, the second insulating film and the third insulating film comprise the same material.

36. A display device according toclaim 33, wherein the second insulating film has a width of 200 to 5000 μm.

37. A display device according toclaim 33, wherein a protection layer covering the second electrode, the first insulating film, the second insulating film and the third insulating film is provided.

38. A display device according toclaim 37, wherein the first substrate and the second substrate comprise glass.

39. A display device according toclaim 38, wherein a gap between the first substrate and the second substrate is filled with an inert gas or a nitrogen gas.

40. A display device according toclaim 33, wherein the adhesive layer has a thickness of 0.05 to 0.5 μm.

41. A display device according toclaim 33, wherein the second insulating film comprises any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

42. A method of manufacturing a display device including an organic light-emitting element formed of an organic compound film sandwiched between a first electrode and a second electrode, comprising the steps of:

selectively forming the first electrode on a first substrate;

forming an insulating film;

patterning the insulating film to form a first insulating film covering an end of the first electrode and a second insulating film provided in a periphery of the first substrate;

forming an organic compound film on the first electrode;

forming the second electrode on the organic compound film;

providing an adhesive layer on the second insulating film; and

bonding the first substrate and the second substrate to each other.

43. A method of manufacturing a display device including an organic light-emitting element formed of an organic compound film sandwiched between a first electrode and a second electrode, comprising the steps of:

selectively forming the first electrode on a first substrate;

forming an insulating film;

patterning the insulating film to form a first insulating film covering an end of the first electrode and a second insulating film provided in a periphery area of the first substrate;

forming an organic compound film on the first electrode;

forming the second electrode on the organic compound film;

providing an adhesive layer which covers the first insulating film, the second insulating film and the second electrode; and

bonding the first substrate and the second substrate to each other.

44. A method of manufacturing a display device including an organic light-emitting element formed of an organic compound film sandwiched between a first electrode and a second electrode, comprising the steps of:

selectively forming the first electrode on a first substrate;

forming an insulating film;

patterning the insulating film to form a first insulating film covering an end of the first electrode and a second insulating film provided in a periphery of the first substrate;

forming an insulating film;

patterning the insulating film formed in the fourth step to provide a convex-shaped third insulating film at least on an upper face of the first insulating film;

forming an organic compound film on the first electrode so as to be in contact with a side face of the first insulating film;

forming the second electrode on the organic compound film;

forming an adhesive layer on the second insulating film; and

bonding the first substrate and the second substrate to each other.

45. A method of manufacturing a display device including an organic light5 emitting element formed of an organic compound film sandwiched between a first electrode and a second electrode, comprising the steps of:

selectively forming the first electrode on a first substrate;

forming an insulating film;

patterning the insulating film to form a first insulating film covering an end of the first electrode, a second insulating film provided in a periphery of the first substrate, and a third insulating film provided between the first insulating film and the second insulating film;

forming the organic compound film on the first electrode;

forming the second electrode on the organic compound film;

filling a gap between the second insulating film and the third insulating film with a desiccant;

forming a layer having adhesion on the second insulating film; and

bonding the first substrate and the second substrate to each other.

46. A method of manufacturing a display deviceclaim 42, further comprising, between the step of forming the second electrode and the step of providing the adhesive layer, a step of providing a protective film covering the first insulating film, the second insulating film and the second electrode.

47. A method of manufacturing a display deviceclaim 43, further comprising, between the step of forming the second electrode and the step of providing the adhesive layer, a step of providing a protective film covering the first insulating film, the second insulating film and the second electrode.

48. A method of manufacturing a display device according toclaim 44, further comprising, between the step of forming the second electrode and the step of forming the adhesive layer, a step of providing a protective film covering the first insulating film, the second insulating film, the third insulating film and the second electrode.

49. A method of manufacturing a display device according toclaim 45, further comprising, between the step of forming the second electrode and the step of filling a gap between the second insulating film and the third insulating film, a step of providing a protective film covering the first insulating film, the second insulating film, the third insulating film and the second electrode.

50. A method of manufacturing a display device according toclaim 42, wherein the second insulating film has a width of 100 to 5000 μm.

51. A method of manufacturing a display device according toclaim 43, wherein the second insulating film has a width of 100 to 5000 μm.

52. A method of manufacturing a display device according toclaim 44, wherein the second insulating film has a width of 100 to 5000 μm.

53. A method of manufacturing a display device according toclaim 45, wherein the second insulating film has a width of 100 to 5000 μm.

54. A method of manufacturing a display device according toclaim 50, wherein the second insulating film has a thickness of 1.0 to 10 μm.

55. A method of manufacturing a display device according toclaim 51, wherein the second insulating film has a thickness of 1.0 to 10 μm.

56. A method of manufacturing a display device according toclaim 52, wherein the second insulating film has a thickness of 1.0 to 10 μm.

57. A method of manufacturing a display device according toclaim 53, wherein the second insulating film has a thickness of 1.0 to 10 μm.

58. A method of manufacturing a display device according toclaim 54, wherein the second insulating film is made of any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

59. A method of manufacturing a display device according toclaim 55, wherein the second insulating film is made of any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

60. A method of manufacturing a display device according toclaim 56, wherein the second insulating film is made of any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

61. A method of manufacturing a display device according toclaim 57, wherein the second insulating film is made of any one of a polyimide resin film, an acrylic resin film, and a polyamide resin film.

62. A method of manufacturing a display device according toclaim 42, wherein, subsequent to the step bonding the first substrate and the second substrate, the first substrate and the second substrate are cut by a CO₂laser.

63. A method of manufacturing a display device according toclaim 42, wherein the first substrate and the second substrate are bonded to each other under an inert gas or a nitrogen atmosphere in the step of bonding the first substrate and the second substrate.

64. A method of manufacturing a display device according toclaim 43, wherein the first substrate and the second substrate are bonded to each other under an inert gas or a nitrogen atmosphere in the step of bonding the first substrate and the second substrate.

65. A method of manufacturing a display device according toclaim 44, wherein the first substrate and the second substrate are bonded to each other under an inert gas or a nitrogen atmosphere in the step of bonding the first substrate and the second substrate.

66. The method of manufacturing a display device according toclaim 45, wherein the first substrate and the second substrate are bonded to each other under an inert gas or a nitrogen atmosphere in the step of bonding the first substrate and the second substrate.

67. A display device according toclaim 1, wherein the semiconductor device is incorporated into an electronic equipment selected from the group consisting of a cellular phone, a mobile computer, a portable information terminal, an electronic book, a video camera, a personal computer, a DVD and a digital camera.

68. A display device according toclaim 2, wherein the semiconductor device is incorporated into an electronic equipment selected from the group consisting of a cellular phone, a mobile computer, a portable information terminal, an electronic book, a video camera, a personal computer, a DVD and a digital camera.

69. A display device according toclaim 19, wherein the semiconductor device is incorporated into an electronic equipment selected from the group consisting of a cellular phone, a mobile computer, a portable information terminal, an electronic book, a video camera, a personal computer, a DVD and a digital camera.

70. A display device according toclaim 20, wherein the semiconductor device is incorporated into an electronic equipment selected from the group consisting of a cellular phone, a mobile computer, a portable information terminal, an electronic book, a video camera, a personal computer, a DVD and a digital camera.

71. A display device according toclaim 33, wherein the semiconductor device is incorporated into an electronic equipment selected from the group consisting of a cellular phone, a mobile computer, a portable information terminal, an electronic book, a video camera, a personal computer, a DVD and a digital camera.

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